Maitreya's Abhisamayalamkara is the most widely studied book in Tibet, where it was brought from India many centuries ago. It is used in all the monasteries to teach the path to Buddhahood, in accordance with the Perfection of Wisdom Sutras. It teaches this in outline form, so it requires a commentary to be understood. The oldest extant commentary is Arya Vimuktisena's Vrtti. Haribhadra, the most influential Indian commentator, drew upon this to write his Aloka. Virtually all of the many famous Tibetan teachers who wrote their own commentaries on the Abhisamayalamkara relied on Haribhadra as their primary source. This is the first of four volumes.